Drug with Activity against the Herpes Virus Family

ABSTRACT

The invention relates to medicine, and specifically to synthetic biologically active derivatives of carbopentoxysulfanilic acid. The novel substance comprises a (2,6-dichlorophenyl)amide salt of carbopentoxysulfanilic acid of general formula: 
     
       
         
         
             
             
         
       
         
         
           
             where X is Na, K, NH 4 ; the drug may be contained in tablets, including sublingual tablets, or in capsules, or in suppositories, or in drops, or in mixtures, or in ointments, creams or other forms for application to the skin and mucosae, or in an oral-buccal film, or in a spray, or in a liquid for parenteral administration, or in chewing gum. A preparation having pronounced activity against herpes viruses is thus produced.

TECHNICAL FIELD

The invention relates to medicine, and specifically to synthetic biologically active derivatives of carbopentoxysulfanilic acid.

The inventive substance has pronounced antiviral activity, mainly against various viruses of the herpes family.

It can be used in medicine, veterinary science and cosmetic science for preventing and treating diseases related to the herpes virus family.

BACKGROUND ART

One of the most serious problems of modern medicine consists in virus infections, the majority of which are extremely difficult to treat or even lack an adequate antiviral therapy. Said difficulty is due to insufficient effectiveness of existing preparations and the fast variability of causative agents that leads to emergence of resistant forms (see http://www.medinfo.ru/sovety/derm/02.phtml).

Similar problems exist in veterinary science.

The most popular preparations for treating wide-spread infections caused by herpes simplex virus are aciclovir, a synthetic acyclic analogue of deoxyguanosine, and Famvir (famciclovir), which transforms in the organism into an active antiviral compound penciclovir (see http://www.rlsnetsu/mnn_index_id_(—)1843.htm). Each of the abovementioned preparations has certain disadvantages. Aciclovir is less active against type II herpes viruses, famciclovir has an extensive list of contraindications, however the majority of circulating herpes viruses currently are resistant towards these preparations that have been used for a long time (P. A. Furman, D. M. Coen, M. H. St. Clair and P. A. Schaffer Aciclovir-resistant mutants of herpes simplex virus type 1 express altered DNA polymerase or reduced aciclovir phosphorylating activities. J. Virol. 1981 December; 3: 936-941) (a copy of the link is attached).

The most popular antiherpetic preparation—aciclovir—2-amino-1,9-dihydro-9-[(2-hydroxyethoxy)methyl]-6H-purine-6-on has been taken as a prototype, (see http://www.rlsnetru/mnn_index_id_(—)290.htm) (a copy of the link is attached):

Its disadvantage consists in the abovementioned fact that the majority of herpes viruses have acquired resistance towards this preparation.

It is an object of the present invention to create a preparation having pronounced activity against herpes viruses.

SUMMARY OF THE INVENTION

According to the invention there is provided synthesis of a novel substance that is a (2,6-dichlorophenyl)amide salt of carbopentoxysulfanilic acid of general formula:

where X is Na, K, NH₄, the drug may be contained in tablets, including sublingual tablets, or in capsules, or in suppositories, or in drops, or in mixtures, or in ointments, creams or other forms for application to the skin and mucosae, or in an oral-buccal film, or in a spray, or in a liquid for parenteral administration, or in chewing gum.

The applicant has not found any sources of information containing data on technical solutions identical to this invention, which enables to conclude that the invention conforms to the criterion “Novelty” (N).

The inventive drug exhibits pronounced activity against the larger part of herpes viruses.

The applicant has not found any sources of information containing data on the influence of the features of the invention on the technical result produced by their implementation. In applicant's opinion, this enables to conclude that the present technical solution conforms to the criterion “Inventive Step” (IS).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further explained, by way of detailed description of examples of its embodiments, without reference to any drawings.

PREFERRED EMBODIMENT

Synthesis of the inventive substance is performed in several stages.

I. Synthesis of Phenylcarbamic Acid Amyl Ester.

8.5 g (0.096 mol) of amyl alcohol were added drop-wise while stirring to 11.5 g (0.096 mol) of phenylisocyanate placed into a beaker. The warming-up of the reaction mass was observed. After 1 hour the mixture solidified in the form of colorless crystals. The output of phenylcarbamic acid amyl ester amounted to approximately 100%.

II. Synthesis of Carbopentoxysulfanilic Acid Chloride.

2.07 g (0.010 mol) of phenylcarbamic acid amyl ester were slowly added while stirring to 17.5 g (0.150 mol) of chlorosulfonic acid heated to 30° C., maintaining the temperature of reaction mass not higher than 35° C. Then the mixture was slowly heated to 50° C. and maintained at 50-55° C. for 2 hours. The obtained sulpho mass was poured to ice while stirring, maintaining the temperature not higher than 20° C. The residue was filtered, washed with ice water until obtaining pH 7 of the filtrate. The residue was air-dried and then dried in a desiccator. Output of carbopentoxysulfanilic acid chloride amounted to approximately 100%.

III. Synthesis of (2,6-Dichlorophenyl)Amide of Carbopentoxysulfanilic Acid.

6.2 g (0.0203 mol) of carbopentoxysulfanilic acid chloride were added portion-wise at a temperature of 85° C. to a mixture of 2.2 g (0.0136 mol) of 2,6-dichloroaniline and 3.23 g (0.0406 mol) of pyridine. Then the reaction mass was stirred for 45 minutes at a temperature of 80° C. Then 20 ml of hot water were added to the mass, the mixture was acidified with hydrochloric acid until obtaining pH 3-4 and cooled down to room temperature. The obtained residue was filtered, washed with water until the odor of pyridine disappeared and then dried. After recrystallization from 80% ethanol the output of target product amounted to 2.5 g (40% of the theoretical value).

IV. Synthesis of the Final Product—Sodium Salt of (2,6-Dichlorophenyl)Amide of Carbopentoxysulfanilic Acid.

0.232 g of caustic soda were dissolved in 5 ml of ethyl alcohol (abs.) and 2.5 g of (2,6-dichlorophenyl)amide of carbopentoxysulfanilic acid were dissolved in 30 ml of ethyl alcohol (abs.). Then the two solutions were mixed and stirred for 20 minutes. After that the ethyl alcohol was distilled off under vacuum. The remaining residue was dried. The output of product amounted to 2.1 g (80% of the theoretical value).

Synthesis of potassium and ammonium salts is performed in a similar way.

Individuality of the substances was proved by means of the thin-layer chromatography method at Silufol UV-254 plates, eluent carbon tetrachloride−isopropanol=2:1. The structure of synthesized substances was proved by means of PMR spectroscopy method.

Antiviral activity of the inventive substance was determined using the model of pneumonia in white mice caused by type I herpes simplex virus.

Herpes simplex virus of type I (strain EC) was accumulated in Vero cells cultured in MEM medium with the addition of 0.2% bovine serum, 50 μg/ml of gentamicin. Virus titration was performed on Vero cells cultured in 96-well plates. Results were recorded after a pronounced cytopathic effect (CPE) appeared in virus control. The degree of intactness of the cellular monolayer was assessed visually, virus titer was calculated as the reciprocal value of Briggs logarithm of the largest dilution of the source material that is still able to produce visually notable manifestations of CPE in the cell culture (CTD50).

For assessing the virus inhibiting action of the preparations, white non-pedigree mice weighing 12-15 g (“Rappolovo” farm, Leningrad Region) were infected intranasally under a light ether anaesthesia with the herpes simplex virus in the dosage of 106 (CTD50)/0.05 ml. The preparation under study was administered intragastrically in the dosage of 50 mg/kg of weight according to a medical-preventive scheme (24 h and 1 h prior to infection, and 24 h and 48 h after the animals were infected). On day 3 the lungs of the infected animals were removed, homogenized in the presence of 10-fold volume of phosphate buffer and then 10-fold dilutions from 10-1 to 10-6 were prepared thereof. Dilutions of the lungs homogenate were used for infecting the intact culture of Vero cells and for titration of virus progeny. Positive reference was represented by lungs of mice that instead of the studied preparation received physiological solution by intragastric administration, whereas negative reference was represented by lungs of mice that received aciclovir in the dosage of 50 mg/kg of weight according to the same scheme. Each experimental group consisted of 10 animals.

The lung material was also subjected to histologic examination.

The data provided in Table 2 show that the preparation has a statistically significant virus-inhibitory activity at the model of herpetic pneumonia in vivo, and surpasses aciclovir with the same dosage.

Determining Activity Against Herpes Viruses of Type I and II.

Herpes simplex virus (strain EC) was grown in Vero cells cultured in MEM medium with the addition of 0.2% bovine serum and 50 mg/l of the preparations under study.

It has been thus determined that the antiviral activity of the inventive substance significantly exceeds that of the aciclovir, in particular against the herpes virus of type II.

The inventive substance can be contained in tablets or in capsules, or in suppositories, or in drops, or in mixtures, or in ointments, creams or other forms for application to the skin and mucosae, or in an oral-buccal film, or in a spray, or in a liquid for parenteral administration, or in chewing gum.

The inventive substance manifests practically identical antiviral activity with X=Na, K or NH₄.

INDUSTRIAL APPLICABILITY

The invention can be implemented by means of known materials and equipment. In applicant's opinion, this enables to conclude that the inventions conform to the criterion “Industrial Applicability” (IA).

Physical and chemical characteristics of the target compounds

TABLE 1 Tmelting, PMR spectrum, ppm X ° C. NH Ar OCH₂ CH₃, CH₂ Na (I) 120 9.75; 9.9 7.2-7.7 4.1  0.9; 1.38; 1.62 K (II) 123  9.8; 10.0 7.3-7.8 4.15 0.94; 1.42; 1.65 NH₄ ⁺ 110 *) *) 4.2 0.91; 1.40; 1.63 (III) (decomp.) *) The region of PMR spectrum or ammonium salt in low field (>7 ppm) is not characteristic: one wide signal is observed, which is caused by the formation of strong hydrogen bonds in the solution.

Results of Virus Titration

TABLE 2 Virus titer in lungs of mice on day 3 after Preparation the infection, Lg CTD₅₀ Reference 3.6 ± 0.15 The inventive substance 1.0 ± 0.11 Aciclovir 1.4 ± 0.34 Morphometric indicators of the pathological process dynamics in lungs of infected animals in the context of application of chemotherapeutic agents at different time stages of herpetic pneumonia

TABLE 3 Term Number of Area of an

inflammation foci inflammation Preparation (in days) in one animal focus in section Reference 2 10 76 ± 5.9 4 10  405 ± 111.3 6 10 343 ± 47.5 Aciclovir 2 8 55 ± 9.4 4 3  58 ± 14.7 6 3 24 ± 6.4 The inventive 2 3 47 ± 7.3 substance 4 2  49 ± 12.1 6 1 14 ± 5.5

Antiviral Activity

TABLE 4 Number (%) of unaltered cells Herpes virus Herpes virus Preparation of type I of type II Reference (non- 10000 (100%) 10000 (100%) infected cells) Aciclovir 7000 (65%) 7000 (70%) The inventive 8000 (80%) 9000 (90%) substance 

1. A drug with activity against the herpes virus family, characterized in that it comprises a (2,6-dichlorophenyl)amide salt of carbopentoxysulfanilic acid of general formula:

where X is Na, K, NH₄.
 2. A drug according to claim 1, characterized in that it is contained in tablets, including sublingual tablets, or in capsules, or in suppositories, or in drops, or in mixtures, or in ointments, creams or other forms for application to the skin and mucosae, or in an oral-buccal film, or in a spray, or in a liquid for parenteral administration, or in chewing gum. 